Mold for concrete blocks



1957 J. J. LIPTRAP MOLD FOR CONCRETE BLOCK 5 Sheets-Sheet 1 Filed Oct. 1, 1965 INVENTOR. Z lP/WAP JAY J.

A TTOR/YEY 1957 J. J. LIPTRAP MOLD FOR CONCRETE BLOCKS 5 Sheets-Sheet Filed Oct. 1, 1965 T WP mu w J A TTOF/YE Y 1967 J. J. LIPTRAP 3,334,857

MOLD FOR CONCRETE BLOCKS JAY J. LIPTRAP ,4 r TOPNEV United States Patent M 3,334,857 MOLD FOR CONCRETE BLOCKS Jay J. Liptrap, 1514 Rainier Ave. S., Seattle, Wash. 98144 Filed Oct. 1, 1965, Ser. No. 492,069 9 Claims. (Cl. 249-119) This invention relates to mold forms for fitting together to mold a large number of blocks of concrete or the like, which blocks will interfit each with adjoining blacks and will so interlock as to produce a continuous patio pavement or the like, wherein each block remains flush with all adjoining blocks, and reinforces and holds in place its neighboring blocks. The invention resides in the mold forms rather than in the blocks formed thereby.

Heretofore, as far as I am aware, interfitting blocks have been made singly, hence slowly, and by the use of molding machines, so that their cost is quite high. It is one of the advantages of the mold of this invention that a large number of blocks can be made simply by filling a mold made up of a plurality of mold forms suitably interfitted in rows, with concrete, and then smoothing off the surface of the whole. When the concrete has set the mold forms can be removed, and all blocks will interfit to form the patio surface, by means of interfitting male and female ridges and grooves along their side edges, these ridges and grooves being molded by the conformation of the mold forms, in a manner to insure their interfitting.

Such molding technique not only assures the correct interfitting of blocks to cover any desired area, but forms the blocks inexpensively, with little investment in molding equipment, and with minimum labor cost.

Since this technique involves the use of a large number of mold forms assembled in a precise relationship, it is an object of this invention to arrange the individual mold forms (or a gang of several joined mold forms)'so that each will interlock with others to retain all in properly assembled relationship. Several forms of interlock are shown herein, each suited to its special conditions of use of the blocks, but all incorporating the principles of this invention.

In particular, in one form of interlock, preferred whenever the blocks must 'bear loads that might be concentrated where these blocks join, it is an object so to form the mold form as to reinforce the blocks in this area, and thereby to eliminate the possibility of their breakage under concentrated load.

It is also an object to form the mold pieces accurately, yet inexpensively, for example by molding them of plastic material.

With such objects in mind, and others which will appear as this specification progresses, the invention comprises the novel mold form shown in the accompanying drawings in several modified forms of execution, and as is described and claimed in this specification.

FIGURE 1 is a plan view of a patio paved with blocks of the preferred form for such use, parts being shown in section to show how the blocks interfit.

FIGURE 2 is a plan View of the mold forms of a style to make such blocks, assembled and filled with concrete, and with parts broken back to illustrate certain joint forms.

FIGURE 3 is an isometric view of the exterior angle of an individual preferred mold form, and FIGURE 4 is a like view of the mold forms interior angle.

FIGURE 5 is a plan view of a completed block, made with mold forms of the preferred form, and FIGURES 6 and 7 are isometric views of the same block, as viewed from opposite sides.

FIGURE 8 is an isometric view of a slightly modified 3,334,857 Patented Aug. 8, 1967 form of block, in juxtaposition to a mold form used to mold the block.

FIGURE 9 is a plan view of joined blocks of a different style, and FIGURE 10 is a plan view of the mold for this style, filled with concrete.

FIGURE 11 is an isometric view of this style block and its mold form juxtaposed.

FIGURE 12 is a plan view of the interlock between mold forms for making this style of block.

The four-sided block is illustrated in its preferred form of elongated lozenge or diamond shape, blunted at both ends, although the same principles can be incorporated in therectangular form of FIGURES 9 to 12 inclusive. The preferred form is shown in a section of patio paving in FIGURE 1, and the block per se isshown in FIG- URES 5, 6, and 7. The individual mold form for making this block is'shown in FIGURES 3 and 4, and several such mold forms assembled in rows to mold this preferred form of block are shown in FIGURE 2. Each such mold form comprises two angularly related sides 1 and 2 which are alike but are numbered differently in order to distinguish clearly between them. The angle at 12 between these sides is an obtuse angle, as shown. At the outer or free end of each side is an integral means to interlock the individual mold form with the angle 12 of two like mold forms. Conveniently this takes the form of a flange 10, 20 of a given thickness, just suflicient that the two adjoining flanges 10 and 20 of the mold forms in the next row of the mold as a whole fit snugly within a notch 21 at the exterior of the angle 12. Normally the flanges 10 and 20 lie perpendicularly to a line joining the ends of the sides 1 and 2.

The notch 21 is not out into the walls 1 and 2, but rather into a male ridge 13 and 23 that extends lengthwise of the respective sides 1 and 2, at the outer side of the angle between these sides. A spaced extension of these ridges, 13a and 23a, extends along the respective sides, but stops short of the ends thereof. The adjacent ends of the ridges 13 and 13a and of ridges 23 and 23a are beveled (see FIGURE 3), as is the outer end of ridges 13a and 23a where they stop short of the ends of their respective sides.

The mold form is formed with female grooves 24, 24a on side 2 and 14: 14a on side 1, at the inner side of the angle, these grooves forming male ridges B and B complementally interfitting with the female grooves C and C formed on adjoining blocks by the ridges 23, 23a, 13 and 13a already described. By stopping the ridges 13a and 23a and the complemental grooves 14a and 24a short of the respective sides 1 and 2, and by chamfering the outer ends of the latter, the block at its point A (FIGURE 1) extends uninterruptedly from its lower support or subbase to its top, and there is no likelihood of its being broken by a concentration of load at this point, for its point is solidly supported upon its sub-base.

The mold is assembled for use by laying a row of mold forms end to end, with their flanges 10, 20 against a marginal form side F1. Then additional mold forms have their flanges interfitted within the notches 21 of the forms already in place. This continues until the area covered defines the number and area of blocks required. Half-blocks D are defined by an end E (FIGURE 2), and at the side opposite side F1 oversize half-blocks G are defined by side F2 and spacers S that occupy the space that otherwise would be filled by the flanges 10, 20. A number of mold forms may be joined or ganged together to facilitate handling. Now, the concrete is poured within the assembled form, and smoothed off to the level of the forms, sides and ends. As many blocks as desired may be made in one pour. When the concrete has set, the blocks and mold forms are separated, and the blocks r'ater' can be fitted precisely, without grouting.

3 The mold form shown in FIGURE 8 differs from that described above in that the ridges 13b and 23b and the corresponding grooves do not stop short of the ends of the respective sides, wherefore the ridges B" extend to the end of the block, as do the grooves C" with which they interfit. This construction will serve where no concentration of load at the tip of a block is expected-as in a side wall facing-but it is preferred that the style first described be used if a load is to be concentrated at such a tip.

The principles of the invention are employed in a mold form for making square blocks; they could instead be of elongated rectangular form by suitable design of the mold form. The individual mold, shown in FIGURE 11, diifers from the one already described in that the exterior angle at 12a is not notched, but is formed with a lug or projection 16, and the end of each side 1 and 2 is notched, at 15 and at 25, to snugly receive the projection 16; see FIGURES and 12.

Such blocks can be used for patio paving, for entranceways, in side-wall covering, etc. They can be varied in color to make up attractive designs. Always they interfit perfectly, and mutually hold one another in place, with or without grouting. As many as desired can be made at one time, inexpensively and without the use of molding machinery.

I claim as my invention:

1. A mold for making simultaneously a plurality of concrete blocks, comprising a plurality of angled strips each defining two adjacent sides of a. block, the several strips being assembled in rows with the abutting ends of strips in each common row adjoining the angle of a given strip in the next row, the abutting ends and the angle being formed with interfitting termini and notches :to interlock, whereby such two rows of strips combine to define enclosures for individual blocks.

2. A mold for making concrete blocks in multiples, as in claim 1, wherein flanges are formed at the free ends of each strip, directed transversely to a line joining the termini of the two sides of the strip, and wherein each strip is formed with a groove at its outer angle, also directed similarly transversely to the same line, and of a width to snugly receive the two flanges of adjoining strips, said grooves and flanges constituting an interlock between the several strips.

3. A mold as in claim 2, wherein the flanges are directed perpendicularly to a line joining the termini of the two sides of the strip, and the complemental flange-receiving grooves are also directed perpendicularly to the same line.

4. A mold for making concrete blocks in multiples, as in claim 1, wherein lugs are outstanding along a line dividing the angle between the two sides of a strip, and

the end of each side is notched, and in cooperation with the like notch of a strip in the adjoining row defines a recess of a size and disposition to snugly receive the lug of an adjoining strip, said lug and notches constituting an interlock between the several strips.

5. A mold as in claim 4, wherein the lugs extend in a direction to bisect the angle between the two sides, and the recess-defining notches are complementally oriented.

6. A mold as in claim 1, wherein the face of one side is indented, to define a male interlocking member in the block, the opposite face of the same side being formed with projections matching the indentations, to define in the block complemental female interlocking recesses to receive the male interlocking members of an adjoining block.

7. A mold as in claim 6, wherein the male-forming indentations are formed as grooves directed lengthwise of the one strip side, but terminating short of the ends and of the angle of that side, and the female-forming projections are formed as complemental ridges along the opposite strip side, also terminating short of the ends and of the angle of the latter side, whereby the grooves and ridges so formed will fit snugly the ridges and grooves of an adjoining block.

8. A mold as in claim 6, wherein the interior angle of the strip is flattened, to space the corresponding angle of the block within the angle where two adjoining blocks meet.

9. A mold as in claim 1, wherein the two sides of a strip are of equal length, and meet at an angle in excess of a right angle.

References Cited UNITED STATES PATENTS 635,952 10/1899 Bass. 785,578 3/1905 Sawyer 249-129 828,727 8/1906 Enos. 1,220,526 3/ 1917 Marshall 249-129 X 1,232,988 7/1917 Smith 25-121 1,406,460 2/1922 Kinzinger 249-129 1,436,033 11/ 1922 Hahn 249-129 1,459,945 6/1923 Boniger 249-129 1,642,247 9/1927 Krause 249-129 X 2,041,289 5/1936 Hewett 249-119 2,309,579 1/ 1943 Duran 249-119 3,017,683 1/1962 Huch et al. 249-129 X FOREIGN PATENTS 520,523 4/ 1940 Great Britain.

1. SPENCER OVERHOLSER, Primary Examiner.

I. HOWARD FLINT, JR., Examiner. 

1. A MOLD FOR MAKING SIMULTANEOUSLY A PLURALITY OF CONCRETE BLOCKS, COMPRISING A PLURALITY OF ANGLED STRIPS EACH DEFINING TWO ADJACENT SIDES OF A BLOCK, THE SEVERAL STRIPS BEING ASSEMBLED IN ROWS WITH THE ABUTTING ENDS OF STRIPS IN EACH COMMON ROW ADJOINING THE ANGLE OF A GIVEN STRIP IN THE NEXT ROW, THE ABUTTING ENDS AND THE ANGLE BEING FORMED WITH INTERFITTING TERMINI AND NOTCHES TO INTERLOCK, WHEREBY SUCH TWO ROWS OF STRIPS COMBINE TO DEFINE ENCLOSURES FOR INDIVIDUAL BLOCKS. 